Property Class 8.8 Steel Fitted (Reamer) Bolts, DIN 609 are supplied to ISO 898-1 property class 8.8. Corrosion behaviour is requires plating (zinc) for corrosion protection, the material is magnetic, and the usable service range is commonly limited to approx. +300 °C; confirm against the coating and the load. In practice this grade is the workhorse medium-carbon alloy class for structural joints.
- Grade
- ISO 898-1 property class 8.8
- Corrosion resistance
- Requires plating (zinc) for corrosion protection
- Magnetic response
- Magnetic
- Service temperature
- commonly limited to approx. +300 °C; confirm against the coating and the load
Property values are typical for the grade. Certified mechanical test data is available on request for production orders.
For fitted (reamer) bolts, din 609 in Property Class 8.8 Steel, the controlling selection factors are corrosion exposure, strength requirement and service temperature. The grade data for Property Class 8.8 Steel (ISO 898-1 property class 8.8) is summarized below together with every size supplied.
Why Choose Property Class 8.8 Steel for Fitted (Reamer) Bolts, DIN 609
The workhorse medium-carbon alloy class for structural joints. For fitted (reamer) bolts, din 609, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
|---|
Corrosion Behavior in Service
Carbon and alloy steel fitted (reamer) bolts, din 609 require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Galvanic & Galling Considerations
For fitted (reamer) bolts, din 609 in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.
Sizes of Fitted (Reamer) Bolts, DIN 609 Available in Property Class 8.8 Steel
| Thread size | Shank diameter ds k6 (mm) | Reamed hole H7 (mm) | Width across flats s (mm) | Head height k (mm) | Common length range (mm) | Property class | Reference standard |
|---|
| M8 | 9 | 9 | 13 | 5.3 | 30~80 | 8.8 | DIN 609 |
| M10 | 11 | 11 | 17 | 6.4 | 35~100 | 8.8 | DIN 609 |
| M12 | 13 | 13 | 19 | 7.5 | 40~120 | 8.8 | DIN 609 |
| M16 | 17 | 17 | 24 | 10.0 | 50~150 | 8.8 | DIN 609 |
| M20 | 21 | 21 | 30 | 12.5 | 60~180 | 8.8 | DIN 609 |
| M24 | 25 | 25 | 36 | 15.0 | 70~200 | 8.8 | DIN 609 |
Dimensions are independent of the material: every size above is available in Property Class 8.8 Steel.
Custom manufacturing · Made to drawing
Need this bolt in a grade that is not listed?
Grade 8 8 Steel is one of the grades the catalog describes. Thread size and pitch, length, property class, drive form, head geometry and head marking are all specifiable — the standard part is where it starts, not where it stops. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom bolt manufacturingSend a drawing
Applications & Industries
Fitted Bolts are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from M8 to M24.
Industries that specify Fitted Bolts
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Gearbox & housing assembly
Split housings that must reassemble in exactly the same position.
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Press & die sets
Located joints carrying shear across the parting line.
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Machine tools
Joints where the bolt locates the two halves as well as clamping them.
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Automotive & transport
Chassis, driveline and body fixings that see vibration and are assembled to a controlled preload.
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Steel fabrication
Bolted connections in frames, enclosures, walkways and weldments, on the bench and on site.
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Energy & infrastructure
Tower, pipework, switchgear and plant fixings specified for long service life and inspectable joints.
Typical applications
- locating two parts within a few hundredths of a millimetre
- reamed H7 holes matched to a k6 ground shank
- transmitting shear on the shank rather than by friction
- joints where the property class is stated on the drawing
- clamping two machined faces to a calculated preload
- bolting brackets, motors and gearboxes to a frame
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Torque and preload
- The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.
Where to use something else
- Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.
Full application guide: where Fitted Bolts are used, how to specify them, and the cases they are wrong for
